Safety razor



May 2l, 1940. Y 2,201,951-- J. l.. BRoNsTElN, Now BY CHANGE oF NAM; J. BRANs.

SAFETY RAZOR Filed July 7, 1937 HHH l? Inventor Josep/7 L. B/'qnstein Aiorne y emma M., 21, 195ol y 2.201.951 sanary Razon.

Joseph L. Bronstein, Milwaukee, Wis., now .by change of name Joseph L. Brans Y Application July 7, 193i, serial Nn. 15am s claims. A(c1. sof-4s) l large number of cutting strokes per second, and

it is therefore preferable to utilize a rotary cutter driven by a conventional electric motor or by .other suitable means adapted to rotate the cutter at any speed which may be required for'obtaining the desired number of cuts per second.

To insurethe necessary contact between the cutting edges of the stationary and rotary cutters,

, it is preferable to utilizev a rigid stationary cutter containing a rotarycutter .esiliently urged there- 20 against by va suitable force such as centrifugal force. The stationary cutter is preferably provided with cutting`apertures in the form of slots,

of such shape as to guide the hair therein, the

skin being drawn into such slotsby the suction of a fan to obtain the closest possible shave.

It is, therefore, an object of thepresent invention to provide a safety razor of the rotary shearing type' in which a rotary cutter is resiliently.

l urged against a rigid stationary cutter.

Another object of the present invention isl to provide a safety razor having apertures so formed as to guide the hair therein.

Another object of the present invention is to provide a safety razor in which a suction is 35 exerted atthe cutting edges of the stationary i cutter to draw the skin into close proximity with the rotary cutter. s

Objects and advantages other than those above set forth will be apparent from the following de- 40 scription when read in connection with the accompanying drawing, in which:

Figure 1 is a view partially in elevation and partially in longitudinal cross-section of one embodiment of the present invention' in which'the cutters are urged into 'mutual engagement by the thrust exertedby the electric motor driving the rotary cutter;

Fig. 2 is an enlarged view in cross-section taken 50 on plane II-II in Fig. 1;

Fig. 3 is a view partially in .elevation and partially in longitudinal cross-section of a modi, ed embodiment of the present invention in which the cutters are urged ment by aspring; l

into mutual eng-age- Fig.'4 is an enlarged view in cross-section taken on plane IV-IV in Fig. 3; y

Fig. 5 is a view partially in elevation and partially in longitudinal cross-section of another modified embodiment of the present invention in 5 which the cutters are urged into mutual engagement by the Joint action of a spring and of centrifugal force;

Fig. 6is an enlarged view in crossfsection taken on plane VI-VI in Fig. 5;

Fig. '7 is an enlarged fragmentary view of tire cutters illustrated in Figs. l and 2, and

Fig. 8 is an enlarged view in elevation of the rotary cutter illustrated in Figs. 5 and 6.

vReferring more particularly' to the drawing 15 by characters of reference, reference numeral I0 in Fig. 1 designates the body or casing of a razor which to be held in the hand when the razor -is being used. Such casing is of generally hollow cylindrical form, and may be made of any suitable material suchas pressed sheet metal .or molded plastic material. If the latter material is utilized, the casing is preferably made in two complementary halves which are held in proper' relative position by means of a cover II and of a is made of steel of razor blade grade having a 30 thickness. as reduced as is found practicable.

- Cutter I2 contains a rotary cutter I3 which is likewise hollow. of fr usto conical shape, `and. which is mounted on a hub Il, Hub Il is fastened in any suitable known manner on a spindle l vIll arranged for rotary movement within casing .v I0 coaxially therewith. Spindle I5 may bedriven by any suitable motor such as an electric n iotor` I6 mounted within casing I0.

Motor I6 may be of any known type and is '40 represented as being of the induction type having a stator l1 provided' with an exciting winding I 8 to be connected to any suitable source of alternating current. The rotor I9 sf the motor ispreferably of the squirrel cage type. If cutter y I3 is to be rotated at the same speed as rotor I9 the rotor is directly connected with the cutter through spindle I5, but it will be understood that gears or other speed changing means may be interposed between rotor I 9 and cutter I3 to ob- 50 tain rotationI of the cutter at .the desired speed. Rotor-` I9 is axially displaced with respect to stator Il to produce a thrust on spindle I5 urging cutter I3 into shearing engagement with cutter I2 by the axial component of the magnetic attraction of stator I I on rotor I9. Such magnetic thrust may take eiect by so shaping spindle I5 that the spindle may take a certain amount of axial play in the bearings 2l of motor I6.

Spindle I5 carries a fan impeller which is preferably of the centrifugal type comprising a plurality of suitably shaped vanes mounted on a hub carrying a disc for guiding the flow of air through the impeller. The fan structure is completed by a perforated diaphragm 23 held in a groove of casing IIJ, the aperture through the diaphragm forming a suction passage connected with the space within cutters I2 and I3.-

Fan 22 is provided with a discharge passage 24 which may conveniently be formed by a lateral tubulure on casing I0. Passage 24 is closed by a bag permeable to air and preferably made of loosely woven fabric for collecting hair sheared by the cutters and drawn into the fan by the suction thereof. The bag, designated by 25, is attached to passage 24 by any suitable known means such as a metal bushing 26 connected to passage 24 by a bayonet fastening. Return of the hair from the bag into the fan by gravity when the fan is inoperative is prevented by a suitable check valve 21. In its simplest form. such valve may consist of a ap of rubber or other yieldable material attached loosely on the end of bushing 26 remote from fan 22 for opening passage 24 only when the fan is operating.

It will be observed that cutter I2 is provided with a plurality of circular rows of slots lying on generatrix lines of the conical surface thereof. Each slot has an elongated rectangular portion extending through the thickness of the cutter wall to form an aperture therein, and is terminate-d at least at one end thereof by a flaring portion of variable depth less than the thickness of the cutter wall. The slots of any row are arranged in alinement with the portions of the cutter wall separating the slots of the other row or rows, so that any generatrix line of the conical surface portion of the cutter provided with slots meets at least one of the slots.

Cutter I3 is likewise provided with slots to form cutting edges lying on generatrix lines of cutter I3 in circular rows opposite the rows of slots of cutter I2. 'I'he slots of cutter I3 are preferably of rectangular shape having the long edges thereof substantially on generatrix lines of the cutter for cooperating with the edges of the rectangular portions of the slots of cutter I2. The result of such slot arrangement is that the cutting edge of any slot of cutter I3 simultaneously engages all points of the cutting edge of any slot of the corresponding row of cutter I2.

The rows of slots of cutter I3 extend over the entire circumference thereof, and the rows of Slots of cutter I2 may be arranged likewise. It is however preferable to provide slots in only a circumerentially-'circumscribed area of cutter I2 as shown on the drawing. 'Ihe amount of heat produced by friction between the cutters may then be reduced by providing cutter I2 with a circumferentially stepped inner surface which is accordingly in contact with cutter I3 only over cir` cumferentially circumscribed areas. Such areas comprise necessarily the area of cutter I2 provided with slots as is apparent in Fig. 2, in which the thicknesses of the cutters are exaggerated to render the drawing clearer, and may also comprise a diametrically opposed area for aiding in guiding the rotary cutter.

When the razor is t0 be used, motor I6 is energized to drive cutter I3 and fan 22. Casing IIJ is heldin the hand and the slotted portion of cut ter I2 is applied against the skin to be shaved. Such slotted portion is then drawn over the surface of the 'skin in the direction of the slots. During such movement the hair is guided into the slots by the flared portions thereof, and as a result of the staggering of the slots of the different rows every point of the area to be shaved over which the razor is drawn is thus faced at some time by at least one of the slots. Each hair thus penetrates into one of the slots where it is sheared in a positive manner by the engagement of parallel cutting edges of the two cutters.

At the same time fan 22 creates a suction in the space within the cutters whereby air is drawn through the slots of the cutters and is expelled through passage 24 and bag 25. The sheared hair is carried by such flow of air into bag 25, wherein the hair is retained. The suction of fan 22 evacuates the space within cutter I3, and the skin is caused thereby to be drawn into the slots of cutter I2 in close proximity with the cutting edges of cutter I3. thus insuring as close a shave asis obtainable even with razors of the conventional unguarded blade type.

In the embodiment illustrated in Figs. 3 and 4 the casing of the razor consists of two half shells 28 of molding material comprising a cylindrical portion enclosing motor I6 and a generally frusto conical portion. The two halves of casing 28 may be maintained assembled b v cover lI and by a ring 29 screwed thereon. The stationary cutter consists of the frusto conical portion of one of the halves of casing 28 having embedded therein a curved plate 30 of steel of razor blade grade provided with the rows of slots above dened with respect to the embodiment illustrated in Figs. l and 2. The inner surface of the slotted area of plate 3U is ground to t the complementary surface of the associated rotary cutter. The rotary cutter may be similar to cutter I3 illustrated in Figs. 1 and 2 or may be a cutter I 3 provided with only one row of slots in which the slots are of sufiicient length to engage both rows of slots of cutter 30.

In the present embodiment rotor I9 of motor I6 is assumed to be axially centered with respect to the associated stator Il, which therefore does not exert any axial thrust thereon. Cutter I3' may then be urged against plate 30 in shearing engagement therewith by means of a spring 3I mounted on cover II and acting on the end of spindle I5. Since the area of contact between cutter I 3 and plate 30 is not symmetrical with respect to the axis of the cutter the thrust exerted by spring 3I causes spindle I5 to be also subjected to a radial thrust which is transmitted thereby to the 'bearings of motor I6. The operation of the present embodiment is identical to that of the previously described embodiment.

The embodiment illustrated in Figs. 5 and b' utilizes previously described casing I0. stationary cutter I2 and motor I6, but in the present embodiment the motor is mounted eccentrically within the casing, and the rotary cutter 32 mounted on hub I 4 is likewise arranged within cutter I2 eccentrically with respect thereto. Cutter 32 comprises a disc portion mounted on hub III and bearing a small number of resilient cutting blades having cutting edges arranged on generatrix lines of a conical surface closely adjacent the inner conical surface of cutter I2. Cutter 32 is urged into engagement with cutter I2 by means of a spring 3|.

When the cutter is rotated by motor I6 the cutter blades are urged radially outward by centrifugal force. By reason of the eccentric arrangement of cutter 32 within cutter I2 the blades of cutter 32 are thus brought into shearing engagement under a predetermined pressure with a circumferentially circumscribed portion of cutter l2, which is also the portion thereof provided with slots. During the remainder of the rotation thereof the cutter blades are out of engagement with the surface of cutter I2 so as to reduce the amount of energy required to overcome the friction between the cutters. The operation of the razor is otherwise identical to that of the previously described embodiments.

Although but a few embodiments of the present invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications ,y may be .made

therein without departing from the spirit of the.

invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. A safety razor comprising a stationary cutter, a rotary cutter, an electric motor having a stator connected with said stationary cutter and having a rotor connected with said rotary cutter, said stator and said rotor being relatively axially displaced to produce on said rotary cutter a thrust urging said rotary lcutter into shearing engagement with said stationary cutter.

2. A safety razor comprising a stationary cutter having a wall provided with slots, each said slot having an elongated rectangular portion extending through the thickness of said wall and terminated by a portion 'fiar-ing outwardly from the slot, the last said portion being of variable depth less than the thickness of said wall, a movable cutter arranged adjacent said stationary cutter and having cutting edges for cooperating with the edges of the rectangular portions of said slots, and means for actuating said movable cutter in shearing engagement with said stationary cutter.

3. A safety razor comprising a hollow frustoconical stationary cutter, a rotary cutter arranged within said stationary cutter eccentrically with respect thereto; and means for causing rotation of said rotary cutter, whereby said rotary cutter is brought into shearing engagement with a circumferentially circumscribed portion of said stationary cutter.

4. A safety razor comprising a'hollow frustoconical stationary cutter, a resilient rotary cutter arranged within said stationary cutter eccentrically with respect thereto, and means for causing rotation of said rotary cutter whereby said rotary cutter is urged by centrifugal force into shearing engagement with a circumferentially circumscribed portion of said stationary cutter.

5. A safety razor comprising a hollow frustoconical stationary cutter, a rotary cutter arranged within said stationary cutter concentrically with respect thereto, and means for causing rotation of said rotary cutter, the inner surface of said stationary cutter being circumferentially so stepped as to be in contact with said rotary cutter over a circumferentially circumscribed area thereof for cooperating with said rotary cutter in shearing hair and for guiding said rotary cutter.

6. A safety razor comprising a hollow stationary cutter, a rotary cutter arranged within said stationary cutter, `means for causing rotation of said rotary cutter, a fan having a suction passage connected with the space within said stationary cutter and having a discharge passage, a bag permeable to air connected to said discharge passage to collect hair sheared by said cutters, and means for preventing the return by gravity of hair from said bag into said fan.

7. A safety razor comprising a hollow stationary cutter, a rotary cutter arranged within said stationary cutter, means for causing rotation of said rotary cutter, a fan having a suction passage connected with the space within said rotary cutter and having a discharge passage, a bag permeable to air connected to said discharge passa ,'e to collect hair sheared by said cutters, and a yieldable flap in said discharge passage for opening said passage only when said fan is operating.

8. A safety razor comprising a hollow frustoconical stationary cutter, a rotary cutter arranged within said stationary cutter and comprising a disc portion revoluble about the axis thereof and a plurality of resilient cutting blades integral with said disc, and means for causing rotation of said disc whereby said blades are urged by centrifugal force into shearing engagement with said stationary cutter.

9. A safety razor comprising a hollow frustoconical stationary cutter, a rotary. cutter arranged within said stationary cutter eccentrically with respect thereto and comprising a disc portion revoluble about the axis thereof and a plurality of resilient cutting blades integral with said disc, and means forv causing rotation of said disc whereby said blades are urged by centrifugal force into shearing engagement with a. circumerentially circumscribed area of said stationary cutter.

JOSEPH L. BRONSTEIN. 

